Sensor for determining the state of parameters on mechanical components while using amorphous carbon layers having piezoresistive properties

Abstract

The present invention relates to a sensor for measuring actual loads acting upon a surface of a mechanical component, wherein as a sensor an amorphous hydrocarbon layer with piezoresistive properties is used, which is preferably doped with at least one metallic and/or non-metallic element and is connected by contacts to a measuring device; the present invention further relates to the use of carbon layers having piezoresistive properties and preferably doped with metallic and/or non-metallic elements as a sensor for load measurements, as well as to a method of measuring actual loads at stressed surfaces of mechanical components, wherein as a measuring sensor an amorphous carbon layer preferably doped with metallic and/or non-metallic elements is used.

1. A method of using an amorphous carbon layer with piezoresistive properties as a sensor for measuring actual state variables at a stressed surface of mechanical components, comprising the steps of:
 providing the amorphous carbon layer having piezoresistive properties therein on the stressed surface, the amorphous carbon layer containing a piezoresistive material;  
 providing a measuring device coupled to the amorphous carbon layer by an electrical contact; and  
 using the amorphous carbon layer as a sensor.  
 
   
   
     2. The method of use of  claim 1 , wherein as state variables the force, which is acting upon the surface, and/or the pressure is measured. 
   
   
     3. The method of use of  claim 1 , wherein the amorphous carbon layer comprises graphitic structures with sp 2  hybridization in combination with diamond-like structures with sp 3  hybridization. 
   
   
     4. The method of use of  claim 1 , wherein the amorphous carbon layer is doped with at least one metallic and/or non-metallic element. 
   
   
     5. The method of use of  claim 4 , wherein the at least one element is selected from Si, Ti, W, Cr, Ta, Nb, V, Zr, Hf, Mo, Pb, Cu, Al, Au, Ag, Pt, Ru, Pd, Ni, Co, oxygen, nitrogen, Ar, F, hydrogen or combinations thereof, in particular from Si, Ti, W and Cr. 
   
   
     6. The method of use of  claim 4 , wherein the at least one element is contained in the amorphous carbon layer in a quantity of 0.01 to 47 atom %, preferably 1 to 45 atom %. 
   
   
     7. The method of use of  claim 1 , wherein the amorphous carbon layer is applied as a wear-resistant pressure sensor onto tools and tribologically stressed components. 
   
   
     8. The method of use of  claim 1 , wherein the amorphous carbon layer is applied as an anti-adhesive pressure sensor onto tools and components. 
   
   
     9. The method of use of  claim 1 , wherein the amorphous carbon layer is used in combination with further functional layers. 
   
   
     10. The method of use of  claim 9 , wherein the amorphous carbon layer is an integral layer component in a multilayer system. 
   
   
     11. The method of use of  claim 1 , wherein the composition of one or more layers varies, in terms of the layer-forming components and/or the concentration of individual layer-forming components, over the layer thickness. 
   
   
     12. The method of use of  claim 1 , wherein the amorphous carbon layer is constructed as a multi-ply layer system. 
   
   
     13. A method of measuring an actual state variable at a stressed surface of a mechanical component, the method comprising the steps of:
 providing an amorphous carbon piezoeresistive layer having piezoresistive properties within the layer and disposed on the stressed surface;  
 providing a measuring device coupled to the amorphous carbon layer by an electrical contact; and  
 measuring the actual state variable.  
 
   
   
     14. The method of  claim 13 , wherein the pressure/resistance characteristic and/or the resistance level of the amorphous carbon layer is adjusted in dependence upon the content and the nature of the at least one metallic and/or non-metallic element. 
   
   
     15. The method of  claim 13 , wherein by virtue of additional thermoresistive measurement by a temperature sensor thermal stabilization is effected. 
   
   
     16. A sensor arrangement for measuring actual state variables of a stressed surface of a mechanical component, comprising:
 an amorphous carbon layer overlaying the surface of the mechanical component; and  
 an electrical contact coupled to the amorphous carbon layer and to a measuring device;  
 wherein the amorphous carbon layer has piezoresistive properties therein.  
 
   
   
     17. The sensor arrangement of  claim 16 , further comprising an insulating layer disposed between the amorphous carbon layer and the surface of the mechanical component, wherein the insulating layer is interrupted at least at one point, for measuring the local stress of the mechanical component at said point. 
   
   
     18. A method of using an amorphous carbon layer with piezoresistive properties as a sensor for measuring actual state variables at a stressed surface of mechanical components, comprising the steps of:
 providing the amorphous carbon layer with piezoresistive properties on the stressed surface, the amorphous carbon layer containing a piezoresistive material;  
 selecting the amorphous carbon layer from a group of hydrogenated carbon layers (a-C:H) and non-hydrogenated carbon layers (i-c);  
 providing a measuring device coupled to the amorphous carbon layer by an electrical contact; and  
 using the amorphous carbon layer as a sensor.  
 
   
   
     19. The method of use of  claim 18  wherein the amorphous carbon layer is doped with at least one metallic and/or non-metallic element.